Nonlupus Full House Nephropathy: A Systematic Review

Abstract

Key Points:

1. Nonlupus full house nephropathy is a rare, complex entity: confusion arises by the low-quality evidence and the lack of consensus on nomenclature.

2. This systematic review supports that systemic lupus erythematosus and nonlupus full house nephropathy are distinct clinical entities, with comparable outcomes.

3. The identification of three pathogenetic categories provides further clues for a shared clinical and diagnostic approach to the disease.

Background: The presence of a full house pattern at immunofluorescence on kidney biopsy in a patient without clinical and laboratory features of systemic lupus erythematosus (SLE) has led to the descriptive term nonlupus full house nephropathy. This systematic review and meta-analysis focus on nonlupus full house nephropathy nomenclature, clinical findings, and outcomes.

Methods: In a reiterative process, all identified terms for nonlupus full house nephropathy and other medical subject headings terms were searched in PubMed. Out of 344 results, 57 records published between 1982 and 2022 were included in the analysis. Clinical data of single patients from different reports were collected. Patients were classified into three pathogenetic categories, which were compared according to baseline characteristics, treatments, and outcomes.

Results: Out of the 57 records, 61% were case reports. Nonlupus full house nephropathy was addressed with 17 different names. We identified 148 patients: 75 (51%) were men; median age 35 (23–58) years. Serum creatinine and proteinuria at onset were 1.4 (0.8–2.5) mg/dl and 5.7 (2.7–8.8) g/d. About half of patients achieved complete response. A causative agent was identified in 51 patients (44%), mainly infectious (41%). Secondary nonlupus full house nephropathy was mostly nonrelapsing with worse kidney function at onset compared with idiopathic disease (P = 0.001). Among the 57 patients (50%) with idiopathic nonlupus full house nephropathy, complete response was comparable between patients treated with immunosuppression and supportive therapy; however, proteinuria and creatinine at onset were higher in patients treated with immunosuppression (P = 0.09 and P = 0.07). The remaining 7 patients (6%) developed SLE after a median follow-up of 5.0 (1.9–9.0) years.

Conclusions: Our data support that SLE and nonlupus full house nephropathy are distinct clinical entities, with comparable outcomes. A small subset of patients develops SLE during follow-up. Nonlupus full house nephropathy is addressed by many different names in the literature. The identification of three pathogenetic categories provides further clues for the management of the disease.

Graphical abstract

Figure 1

Flow diagram of the study selection process. *Some authors used the names in brackets to refer to nonlupus full house nephropathy: In this case, records were not excluded.

Figure 2

Roadmap of SLE-like entities. SLE-like entities are shown below and were excluded from the evaluation. Definitions of SLE-like entities for the purpose of this analysis are listed in Table 1. LN, lupus nephritis; SLE, systemic lupus erythematosus.

Figure 3

Distribution of names referring to nonlupus full house nephropathy in the 57 PubMed records eligible for analysis. A total of 17 different names have been used to identify patients with nonlupus with full house pattern at kidney biopsy, with “lupus like” (26%), “non lupus full house” (12%), and “full house” (12%) nephropathy being the most used terms. Moreover, each name may refer to different entities and/or different pathogenic groups: 54% of reports described patients with secondary disease, 25% with idiopathic disease, and 4% with apparent idiopathic disease, who developed overt disease during follow-up. The remaining papers referred to more than one category.

Figure 4

Diagnostic roadmap proposal. Dotted lines reflect pathogenetic pathways needing further investigations. The supposed mechanisms behind the diseases are reported in brackets (see text for further details). ACR, American College of Rheumatology; EULAR, European League against Rheumatism; IC, immune complexes; IF, immunofluorescence; TRIs, tubuloreticular inclusions; SLICC, Systemic Lupus International Collaborating Clinics.